Send it back to Acer and demand a working system or your money back.
Personally, I'd go with the money back option, Acer is pretty bottom of the barrel in terms of overall quality. Vista will actually work fairly well if you run it on hardware that isn't crap.
since I have had my new desk top computer I have had nothing but truble. My computer is an Acer AM5100 with Vista Home Premium. the first problem I have was with the DVD Burner drive, it did not recognize any CD or DVD. when I called Acer they said it was probobly a Vista compatability issue, so the Tech told me to do a system restore and when I did it came back saying that system could not restore and has not changed.. I finaly fixed my DVD drive Issue by swaping out the Drive Acer was kind as to send me a new with solved that problome.. But I still could not do a simple system restore I have tryed over and over with different Issues and samething. I called Acer back and they recomeded that I use the restore aplication disk.. I did wich erased all my data and I still have the same problome.. I also have a problem whith internet explorer it stops while online and frezzes the says internet explorer not respondingafter sending this info to fix this all I get back is Enhanced On - Access Anti-Malware Protection stoped working and was closed.. A problem caused the application to stop working correctly. windows will notify you if a solution is avalible. this happens all the time I can berly chaeck my emails ... Please help if theres any way to fix this.. windows vista is driving me crazzy.. Thanks