Thanks! I'll do that as well, although it seems to be working perfectly now (except for the issue with HDRtist and Inkscape). I removed the bottom case to check whether the battery was bloated, which would explain the situation, and later when I turned it on the problem was fixed. I don't know why or how... I'm afraid it might happen again, though.
What about the applications that won't open? Do you have anything in mind?
I have read of people saying Resetting SMC fixes stuck touchpad drag problems. In order to do this you must typically remove the battery. I think it was the act of battery removal that fixed it and not the act of clearing SMC memory.
If your Macbook battery is removable and is located directly under your touchpad a bloated swollen battery could be the problem.
- Remove battery
- Connect to magsafe power and boot up.
- Try using your touchpad
If this fixes the problem you likely have a swollen or bloated lithium battery. My symptoms on my 15" late 2008 Macbook Pro were that the touchpad acted like it was stuck in drag mode. The bottom left and right touchpad switches would not click or took great effort to press. I had to hit the touchpad very hard for a mouse click to be recognized. It also screwed up opration of my bluetooth mouse. I noticed several months earlier the battery cover no longer closed tightly; there was a gap. I should have been more curious as to why.
MacBook Pro (15-inch, Late 2008) MacBookPro5,1
FB4700LL/A ( MB4700LL/A )
"Battery bloat or “swollen batteries” is a common occurrence among older lithium ion batteries. It is commonly caused by overcharging a battery and then leaving it unused for a long time. It may also be caused by extreme changes in temperature. More often than not, battery bloat essentially “kills” the battery, rendering it unusable or unsafe for further use."