Dear all. Hi I'm new here so please forgive me if I sound like a moron. I'm running XP 64 on a Dell T3400, Intel Extreme 2 quad core @ 3 GHz, 4 Gb RAM, 2 x 500 Gb SATA HD's, and an NVIDIA Quadro FX570 256Mb running 2 x 17" standard Dell flat screen monitors at 1600x1200 @ 60 Hz. Start up is nice and zippy, but after about an hour and running several applications - nothing heavy, word 2007, firefox, outlook, excel 2007, acrobat 9 is pretty standard - the whole system slows down to a crawl. The first symptom is the Start Menu staying open and then after that it's reminiscent of running computers 18 years ago when you had to wait for everything to catch up with your clicks and typing. Closing all apps fixes the problem, but after an hour then everything starts to grind again. Everything is up to date - all software and systemware - and all needless features disabled - like shadows and the like. I've got McAfee running for viruses, malware, spyware, etc. and that turns up blank. I've defragged the HD. Tinkered with the page files. All to no avail and I'm out of ideas. Is there anything I might have missed? Is upgrading to Vista the answer to my dreams or does that have similar issues? The nag is of course that all this has cost a small fortune and I was more productive on a 32 bit version of XP with a P4 @ 3 GHz, 1.5 Gb RAM, and a 200 Gb ATA HD. In fact, I'm even more productive on my Dell Latitude Netbook running an Intel Atom @ 1.6GHz