How did you clean/erase the HDD before you install win 7 ?
When you install, did windows make a small partition smaller then 350 MB ?
What brand of HDD, go to the MFG site, get utility to erase the HDD, NO FORMAT -ERASE the HDD - ZERO write.
Start with ONE stick memory and try. Make sure windows makes small partition when you see your HDD in list to install.
If you have any storage drives, where you keep APPS, check with best Anti-virus, Gdata, Avira, Eset, Fsecure, Avast, Norton. Fsecure has online scanner, Avira has a rescue disk.