1. Put drive back in old computer
2. boot with Windows 7 Repair CD
3. in command line, run
4. you also might try running this in command line
sfc /scannow /offbootdir=c: /offwindir=c:/windows
part 4 scans necessary windows files and attempts to replace/repair corrupted or missing ones
The only issue I had this year was with a laptop I ordered for my grandmother through Newegg. Ordered on Dec 7th (Sat) and was expecting it on Wed, possibly Thurs. FedEx waited 2 days before they even got it from Newegg (in Cali). Took a whole week. I typically get stuff through UPS only takes 2.5 days or so. Had to pay to ship it to Michigan from Kansas and it only took 3 days with UPS.
As far as the CX units go the CX430 is all right for the cost, the rest are total garbage. Like I said, for an OEM replacement that should do just fine. I'v also used the Antec NeoEco series before. Are there any stores other than the one you posted you can order from? Their selection looks quite limited