Get an external storage device or a Time Capsule or equivalent, and fix the most critical problem first — get backups going. Definitely before you try anything like a reload, and preferably sooner. (Time Capsule makes backups easy, too. Backups just happen, any time you're in range of the WiFi.)
Boot the recovery partition and — as ericaghg suggests — test. Or boot the installation DVD or a purpose-downloaded and created bootable USB device, if that's what is appropriate for your Mac, and test there.
Clean off the trackpad, per Apple cleaning recommendations. I've had wacky trackpad behavior with various MacBook Pro systems, behavior that was resolved after the trackpad was cleaned. Sometimes it doesn't take very much to foul the trackpad response, too.
If you have any haxies or add-ons or plug-ins that access with the trackpad, remove those. (This case usually shows up when you test from the recovery partition or a safe-mode boot or an external boot, and that works. Or if things work from a different purpose-created login, for that matter.)
I'm also running currently-patched Macs, and have not encountered trackpad issues.