I always install/update TWS using an admin-account. I run TWS in a restricted-user account. So far I have not experienced any hang-ups when launching TWS. Currently using: TWS 885.7.
It could relate to the java install rather than the tws jars though. And the new java may be more pedantic than the older versions. I've always used the same accounts for install and running so can offer no other observations.
I think I found the solution to my problem. It seems that the jre since update 6 (as near as I can figure) has been running more restrictively. For example with update 7 my preference were no longer being written to my jts directory (which was under my usual login id as power user). Prior to this, in fact for years, I had no problem with this. Now with the RC jre it wouldn't load past the splash screen. Today I went to the security tab for the jts folder and gave the power user id all rights. Now TWS starts fine with the power user login.
TWS = The Worst Software You have to use something like Ninja Trader if you're actively day trading. Swing traders could probably suffer through TWS since timing isn't as critical.
I can't remember the last time the Market Statistics screen worked. I get only trin and tick, none of the other data. Other scanner pages work fine.