2 cc'ts of 14/2 will be enough power for what you want, assuming you only plan to use one tool at a time, which with only one person working, makes complete sense. However, I'd be slightly concerned at 100' of the voltage drop, especially with power tools. Electric motors don't like lower voltage. They overheat, don't run as fast as specified, and will not last as long on lower voltage. Now, about reconnecting the cut cables: You need to reconnect the cables using a junction box if above ground, using a waterproof J box. If it's below grade, then you'll need a UF splice kit, no junction box.
Based on your info, I'd suggest pulling new UF through the conduit. If you ever want 240V in the garage, you'll need 3 wire + ground cable. If it were me, and you had large enough conduit, I'd pull 8/3 or even 6/3 cable and put an 8 space sub panel in the garage. I'd put a DP 40A on the 8/3 or a DP 60A breaker on the 6/3 in the main panel to feed the sub. With the lower gauge wire, voltage drop is less of an issue at 100'.

I almost forgot. If your conduit is too small for 8/3 cable, you might pull individual #8 THWN wires. They are easier to pull than cable and may fit where the cable didn't.

i dont think the conduit runs the entire length, only where it enters and exits the ground. and where the wires are cut is indise the house, i should be able to use the regular metal j boxes, right?

also, would the ccts need to be gfci protected at all?

OK, this extra info you provided allows me to complete my suggestions. Unless you want to re-trench, leave the existing buried cable. Use a regular metal J box in the house for splicing.

I can only quote you CEC (Canadian Electrical Code). Any recepts mounted externally on the garage walls within 2.5m of grade must be GFCI protected and on a dedicated cc't. We are required to have at least 1 external recept, dedicated, GFCI protected, for outdoor appliances or tools. We are also required to have 1 external recept, dedicated, GFCI protected, for each driveway. We are also required to have 1 recept, dedicated, GFCI not necessary, for each car space within the garage. Garage light fixtures and openers can also be placed on these dedicated non GFCI interior garage cc'ts.The reason for these cc'ts for each car or driveway is that where I live it gets very cold in the winter (normal lows are -20F to -30F and occasionally -40F) and block heaters are a necessity if one needs their car to start Dec through Feb.

You are not allowed to run two separate circuits to an out building. If you want two circuits you must run them as a multiwire using a single cable and a shared neutral.

joed,

knowing that it changes stuff then. can i use 1 cct for inside the building for power and lights, and take the other and put an outlet on the OUTSIDE of the building?

bigbird quoted the cec about gfci protection, what does the nec say about it?

if it changes anything i called it a garage, but it wont be used for parking... as it is 100' from the house, all the way on the back of the property line with no driveway to it. maybe a better term would be "barn". it has a 1 car bay with a 20x10 workshop next to it.

*IF* i can only use 1 cct, do all the outlets need to be gfi protected? how many outlets/lights will be allowed on the cct?

All the receptacles, both inside and out, will need to be ground fault protected.

so would it be okay to run the other cct for outlets OUTSIDE the garage/barn?

You can use the circutis any way you please. GFCI is required for inside and out for normal use receptacles. Receptacles on the ceiling for a garage door opener do not need GFCI. GFCI is not required for lighting.

If he uses a GFCI breaker in the main house for the circuit that feeds the garage does he still need to use GFCI receptacles in the garage?

No, a GFCI breaker will protect all receptacles on that cc't. However, GFCI breakers are expensive, and if it tripped, he'd have to go back into the main panel in the house to reset it. I'd put one GFCI recept on each cc't in the garage and feed other recepts downstream off the load side.

"2 cc'ts of 14/2 will be enough power for what you want, assuming you only plan to use one tool at a time, which with only one person working,..."

Maybe not.
Many 10 inch table saws need a 240 V, 30 A (or more) circuit.
The same with larger band saws and jointers.
Even some larger routers need a 20 A 120 V circuit.

An air compressor larger than a pancake size will also need 240 V.

"An air compressor larger than a pancake size will also need 240 V."

i have a craftsman 15 gal that only requires 15A, as per the manual...

and with regards to the tools that require 240v 30A, well lets just say the chances of me buying something like this ANYTIME soon is slim to none.

i plan to use the garage to change the oil in the car, build the kids a toybox, etc. not going to me a major woodworking shop or anything. the biggest task i plan to undertake is restoring an old ford garden tractor using mostly the air compressor.

i am not worried about having enough juice to work out there.

"An air compressor larger than a pancake size will also need 240 V."

Not true at all. I have a piston air compressor, Ingersoll-Rand, 24 gallon, 120V. It's never tripped the 15A breaker yet.

Brickeye most 20-30 gallon compressors that are sold at such places as sears or home depot use only 120 V and 15 amps

a 33 gallon craftsman upright with a 2hp motor only uses 15 amps according to the specs.