Windows 7rc running extremely slow with 100% cpu usage

Hi.I just installed windows 7 rc on a second hard drive(i have vista home premium on the first).It was a clean installation.
It's running extremely slow however and in task manager it shows the cpu usage at a constant 100%.When i say slow,i mean ridiculously slow!
I'm not running any programs and have no anti-virus installed.The only suspicious thing i can think of is that it took an incredibly long time to install (6-7 hours)
I've reinstalled but the problem remains
I would appreciate any help.Thanks

Q6600@2.4Ghz ,4gb pc26400 ram ,Geforce 9500gt

Hi,thanks for the reply.I haven't installed any driver,i suspected the hard drive as well so i've removed it and installed a new sata drive,the old one was a pata.
I'm installing again now but it's still taking forever to install and that's not good.

Hi, you dont mention what type of HDD you're using but if by any slim chance you're using an old drive and it's a PATA one rather than SATA, it may be worth checking if it's in PIO mode rather than DMA.

Found the problem,removed one of the 2gb ram sticks and now it runs fine with the sinle 2gb stick.
The 4gb work fine on the vista 32 bit and the only main reason i downloaded the 64 bit windows 7 was to use all 4 gigs.New problem now lol!
Thanks for the help.It was installed on a pata drive and i removed it and installed a new sata drive but as i mention above that wasn't the problem.Doesn't matter though ,i've been wanting to change the hdd and get rid of the ide cable in the process!