Updating system but keeping old hard-drive...newbie question

[Brockson7]

My parents lap-top died.

I am giving them most of my old system (my 1st ever build):
DFI nf4 SLI-dr
amd 3500 venice
enermax noisetaker 600w
nec dvd burner
ozc plat 2x1gb ddr 400 2-3-2-5
evga 7800gtx 250 mb
250gb maxtor 10 16mb sata

I just ordered:
asus p5b deluxe
intel e6420
evga 7100gs
asus sata dvd burner
80gb wd 8mb sata
cosair xms2 ddr2 2x1gb eep
cosair 620 modular psu

my parents will get the new 80gb hd and 7100gs while I get all the awesome new stuff...and keep my 7800gtx (untill they release a dx10 cards that actually perform in dx10).

my question is: What do I need to do to keep all the..hahem files...that are on my 250gb hd (windows xp pro) and boot properly?I read the past post of someone buying a new hd and then adding the old hd later but I am just trying to use my old hd.
i.e. do I need to delete my drivers for my new intel stuff? would I be better off just buying an external hd and downloading my schoolwork and pron onto it and then doing a clean install on the maxtor?

hopefully this post makes sense and hasnt been posted lately...I couldnt find it, but I am lazy. All input is much appreciated :?

 

[Brockson7]

thanks for the quick reply and helpful input!!!