Weird issues trying to boot x61t in Vista x64

[noetus]

I recently installed Vista 64-bit on my x61 tablet and everything seemed to work fine for a week or so until I tried using it in tablet mode, with the pen. At that very point it starting locking up, at first just with some of the open apps and then gradually the whole system.

I rebooted, tried the pen input, and the same thing happened. Tried a couple more reboots, same thing.

Then the system stopped logging me in entirely. Now when I try to boot the system it boots fine in safe mode, and I can use msconfig to try a minimal boot. However, it won't boot past the login screen. If I try a finger swipe it simply locks up on the 'Please wait' screen (with the 'busy' indicator revolving) or simply does nothing; if I try using the password login the little user icon simply disappears as soon as I select it and the machine then stops responding (with a totally empty login screen, never seen that before).

I tried using system restore TWICE, to two different earlier states when it was working. This had made absolutely no difference whatsoever - I still get exactly the same problem. Which seems like it should be impossible (is this a system restore, or isn't it?).

I also tried using a 'repair system' from the Windows install disk and that did nothing, as well. The upshot is that I can no longer boot into my machine, except in safe more.

[noetus]

OK so I have managed to obtain an event log of what is happening when I attempt to log in - to the initiated this should mean something, though not to me. The User Profile Service stopped, but I don't know why:

Level Date and Time Source Event ID Task Category
Information 11/12/2008 2:56:35 PM Microsoft-Windows-User Profiles Service 1532 None "The User Profile Service has stopped.

"
Information 11/12/2008 2:56:34 PM Microsoft-Windows-Winlogon 6000 None The winlogon notification subscriber <Wlansvc> was unavailable to handle a notification event.
Warning 11/12/2008 2:56:34 PM Microsoft-Windows-Winlogon 6000 None The winlogon notification subscriber <GPClient> was unavailable to handle a notification event.
Information 11/12/2008 2:56:34 PM Microsoft-Windows-Winlogon 6000 None The winlogon notification subscriber <SessionEnv> was unavailable to handle a notification event.
Information 11/12/2008 2:56:34 PM Microsoft-Windows-Winlogon 6000 None The winlogon notification subscriber <Sens> was unavailable to handle a notification event.
Warning 11/12/2008 2:56:33 PM Microsoft-Windows-Winlogon 6000 None The winlogon notification subscriber <GPClient> was unavailable to handle a notification event.
Information 11/12/2008 2:53:28 PM Microsoft-Windows-LoadPerf 1000 None Performance counters for the WmiApRpl (WmiApRpl) service were loaded successfully. The Record Data in the data section contains the new index values assigned to this service.
Information 11/12/2008 2:53:28 PM Microsoft-Windows-LoadPerf 1001 None Performance counters for the WmiApRpl (WmiApRpl) service were removed successfully. The Record Data contains the new values of the system Last Counter and Last Help registry entries.

[noetus]

So I've made some headway with this. Turns out (after much trial and error with msconfig) the Windows Search service is unable to start, and hangs the system on logon. Disable the service, and Windows boots and logs on fine. Attempting to start the service at this point causes a long wait and then the system slowly locks up and becomes totally unresponsive, requiring a power cycle, restart in safe mode, and disable the service again to fix. It does seem as if the system is stable as long as Windows Search remains disabled.

Several things surprise me about this:

(1) Why would a Windows Search service problem disable the entire system?

(2) Why doesn't doing a system restore, to a point before the problem materialized, fix the problem?

The problem is still unresolved - I don't know WHY windows search service is causing this issue (or even if it is the service that is causing the issue, or some other resource the service requires).

I realize this is now a generic Vista issue, not an X61 tablet issue. Can this thread be moved to the Vista section, please?