After many hours of trying I may have been able to kill the "Home Search Assistent" and "about:blank" hijacker, which I think may also be known as CoolWebSearch. I'm not a PC expert but I am PC literate (I am an embedded SW engineer) and I wanted to share my experience in case the information could be of use to someone else.
When I began trying to rid my PC of this problem I was using NoAdware, Norton Antivirus and YourUninstaller (trial version). It soon became apparent that Norton Antivirus was powerless against this threat. It completely failed to detect it much less wipe it out. NoAdware was able to find some registry entries that were called "troj_agent.BM" that appeared to be related to CoolWebSearch and would wipe them out but if you ran NoAdware again a few minutes later they were back in again. Not much use. Also while working on the problem I tried to use the uninstaller several times on "Home Search Assistent" and "Shopping Wizard" and
"Search Extender". Each time it would uninstall them but they would soon reappear.
I then downloaded AdAware and it was able to find many more suspect files and registry entries than NoAware and wiped them out. It also uninstalled the "Home Search Assistent" trio but they would reappear just as before. Also, if memory serves, AdAware actually wiped out NoAdware from my PC. Not sure why. Frustrating...
I then did some more research and found the Intermute software web site. They have a Spyware killer that is targeted at CoolWebSearch called CWShredder. It is available for free as a 30 day trial along with their SpySubtract general purpose spyware killer. I then began hitting CoolWebSearch with a five pronged attack. I ran CWShredder, SpySubtract, AdAware, YourUninstaller and Norton Antivirus in a fairly random order several times each and sometimes after booting up in safe mode and sometimes in normal mode. The two spyware killers appeared to each be able to find some spyware that the other could not. But after attacking CoolWebsearch for the better part of a day it appeared that it was completely gone. It has been over 24 hours and there is nothing in my registry and nothing has reinstalled itself. It *appears* to be gone.
Some notes: Norton Antivirus never found anything to do with CoolWebSearch so you can probably get good results without using it. At several points both SpySubtract and AdAware would hang up when I tried to delete the suspected files. This only happened while in normal mode and it appeared that it only happened when CoolWebSearch was found as a running process. Is it possible that CoolWebSearch was stopping them? Anyway, I would then boot up in safe mode and repeat the attack procedure and the spyware killers would run fine. I would then go back to normal mode and start attacking again.
I hope this information can be of use to someone.