I have seen machines with admittedly minimal base memory run out of physical memory before they are even done booting meaning they are thrashing the hard disk just to run a browser.
I have seen a browsers start up with 6 or more search toolbars. The machine may boot OK but when they say "it runs slow" they mean it takes a long time to start the browser.
The cleanup process is pretty fast anymore. The problems are obvious, stop the stupid start up options and uninstall toolbars. Honestly what home user runs Acrobat Reader often enough to need it to preload? I doubt very many professional users need that.
I hate all the search toolbars. Each browser basically comes with one already. I know, these things drive money and traffic to someone else but they are of no use to an end user. We really are hardly in control of our machines anymore. I have made the mistake of pressing [OK] too quickly and not unchecking the "install toolbar X" checkbox when I am updating Java or Flash or some other web helper. Drives me nuts forcing me to clean it up right way wasting my time. Multiple that by the number of computers in the house and it really stinks.
For my home machines I usually take a Sunday morning and work on one machine carefully updating things including various open source programs I use. Try to get into the "read everything" mindset and do it right. I like programs that let you download them once and install on multiple machines. Stinks when you have to tie up your internet connection on every machine because there is only the option to update on-line.
Training friends and family members does not seem to help. Same people, same problems at least twice a year. This has gotten out of control. Beginning to think I need to write a program that either helps clear this crap up or monitors for things trying to run and stopping them. I know AdAware will do that but the pop up messages are not that helpful to the average end user. They really need something that is super friendly saying "If you allow this Kevin will have to come over again and clean up again".