I quickly browsed through this thread and noticed, reg cleaner, temp file cleaner, defrag, etc. I didn't see specs, apps loaded in memory at start, how many apps you normally have running in a session, etc. I have a few questions.
1. What programs are loaded into memory when the computer starts? If there are many, are there any that you can do without? Reducing what starts can help with low memory problems. Running very few apps simultaneously will help too. How many apps do you run simultaneously?
2. What are the system specs of your old computer and your newly acquired computer. I have a dual core laptop and a pentium 4 single core pc. I don't have much patience anymore to sign on to the Pentium 4 single core after using the laptop with the dual core processor. Most tasks on the dual core laptop happen without delay.
My question is, are you comparing apples to apples? Did your previous computer have better specs than your newly acquired computer?
3. What about the operating system condition? Fully updated? All programs and drivers updated? Is it clean? Has it crashed or ever had a virus that has damaged anything important?
4. What antivirus program was installed before avast and how did you remove it?
5. Were you given any recovery cd's?