I have Vista Basic x64 and have just had the hardest time finding much software that works on my system. I did have Webroot SpySweeper running fine but the company stuck Antivirus on the program without me letting it and I already have an av. I've had all kinds of problems getting Spyware Doctor to run right. Their website says that if you start having problems you can go through Data Execution Prevention and make an exception for it, but that's a hassle.
I haven't be able to get Ad-Aware to run, I don't think much of Spybot and Windows Defenders...well..what more do I need to say. I have run Super Anti-Spyware in the past successfully, but the jury is still for me as to if it ever could find anything. I don't know much about Spyware Terminator, I am curious about the new AvanQuest Double Anti-Spy and a-squared turns up way too many false positives