My new Lenovo T410 has slowed to a crawl. How do I fix it?

Given that you have checked a lot already, it might be a possibility that there is actually nothing wrong with the software/programs but that the SSD itself is causing the slowness.

Given the information I found here and here it seems this SSD has no TRIM support but relies on its internal garbage collector. Maybe you should give your computer some hours with at least disk I/O as possible so it has a chance to execute a run.

Switch the power plan to Maximized (so it's not sent to sleep), disable any network connections (no new Updates), disable the anti-virus software and logoff. Then give it a night, turn everything on again and see if it's getting better.

Maybe cooling issues, that's what it narrows down in my case usually when it comes to Lenovos. Check if your fan works, check system settings and disable services you don't use in msconfig utility (google it), try to use some less resource demanding security solution such as AVG or NOD32 instead of Symantec od F-Secure, defragment your HDD, update drivers.

Based on the info, it sounds like a hard drive sub-system bottleneck of some kind.

As for tools to check out system troubles/slowness, have you checked out Windows 7's in-built Resource Monitor? (Start→All Programs→Accessories→System Tools→Resource Monitor, or just use the search box :) )