Unfortunately the problem isn't avast!
WRONG! The problem IS avast!
but a system that's starving for additional Ram
again WRONG! The system is working fine even with several tasks running parallelly - only avast is consuming more than available - the problem IS avast!
and one that also needs additional Hard Drive space.
and even WRONGer!!! 3GB of free space on boot-drive and 10GB free on second drive is more than enough!!!
If you fix these 2 items, you'll have a well behaved computer again.
There is nothing to fix but avast! The PC runs fine for more than a decade now - and the only problem is avast and nothing else!
Without it, you'll have nothing but headaches.
Come here and put more RAM than physically possible into that PC!!!
... update from today:
Total time: 30:41
Download time: 2:55 (what is long - as here is a 25MBit internet access available).
Downloaded files: 17 (1'748.61 kByte)
The problem IS avast; you cannot do anything else as long as avast is updating; if that lasts for about less than 2 minutes, it would be acceptable - but more than half an hour is not!
Btw: avast 4.8 has the better engine, even if the PC is not responsive for several seconds at a certain moment. but an update NEVER last so long as with avast 8!