well sorry to return to this old days MS crap...
but IE8 is yet in use by me and therefore its problems remain same.
z above advice is nice but doesn't work 4 me in full, so here is small update to this remedy in meaning of its applicability to Win7sp1x64 Ultimate laptop.
pls do same to 2 more registry keys as below:
UPDATE: well.. unfortunately this also didn't solve a problem completely in my case but another advice from here: IE8 (Win7) not closing all processes
** Solution 2 **
In addition to the above, you can try disabling IE8's memory protection and
see if it helps. Start > Control Panel > Internet Options > Advanced > under
'Security', uncheck 'Enable memory protection to help mitigate online
attacks' > OK
maybe looks working much better for me. at least duing last couple of hours
while z total 3 registry settings as above remain same with new dword key TabShutdownDelay = 0 added.