Ok I got a problem with 2.26 
sometimes after 15 - 30 minutes of making meshes I press A to de-select vertices and the A to select them all…now sometimes, don’t ask me when or why…when I do this blender starts rendering an animation, so I press escape to stop it… afterwards the g key (grab) is unresponsive, maybe other keys too… S and W still work…BUT my A key only tries to render animations afterwards even if pressed once…
this stops as soon as I move a vertice with the right mouse button however, but still it is very irritating :-?
hurm…that’s not good. I still use 2.22 for the most part 
hehe, that happened to me on occasion in version 2.23 also.
stephen2002: blender 2.22? when did that version come out? and dont tell me it was before 2.23…
hey hoxolot!!
have you considered that you have your arm resting on the Alt key
because Alt+A puts it into the animation mode, which just goes through the set frame lengths in the 3d window
but i supose you already knew that.
also perhaps your keyboard is broken or the Alt key is stuck in some way.
Hmmm thats my only sugestion.
Alltaken
This has also happened to me. It is as if the alt key is depressed. So the animation is played instead of de/select. I am not sure if it is linked to having num lock on or not so you could look at that, as that does cause problems. Maybe some driver thing?
I have win/me (yes LINUX is better, just when I get it set up correctly …)
I have not had this under UNIX although the minus key does not work under UNIX.
Rob.
This happens to me (I run XP). Blender seems to think the alt key is pressed when it isnt. Normally i just press alt a few times and it starts working again.
in my pc sometimes when i press F12 for rendering instead of rendering, the sound editing window opens.i used to exit blender and re-open it and worked fine.then afterwords i realised that if i refresh the desktop(windows) minimizing blender it starts woking fine.did you refresh the desktop like me?it may solve the problem.
kos, you need a new keyboard, or a pair of glasses. that f12 thing is getting serious.
blendermax: before 2.23 
Honestly I don’t really keep track. I tried 2.23 when it came out but I think that it was less stable when rendering than 2.22. I have 2.25 installed on my computer but I have not been using Blender much recently.
this has happened to me alot not only on xp but the quickest way to slove it is to manually rotate the view point and then you should be back in business.
I love to slove stuff.
It’s not a blender problem it’s a windows problem that something in blender triggers on occasion.
The problem is that when you press alt (or some other key), the computer sees it and sets a flag somewhere in memory, then when you release it it doesn’t notice and the key remains “pushed” according to windows.
It often happens with me if I use Alt+LMB to rotate the 3d view. If I release Alt before LMB it still thinks I have Alt pressed.
Just press the button and release it again to fix. I usually press both shifts, ctrls and alts once each and that fixes almost anything like this.
This works on some computers:
Press any key. Press Windows (Start menu) key. Release other key. Release Windows key.
The key you pressed first will be “held” until you press it again if you do it fast enough.
it appears to be the flags issue mentioned above
but it isn’t limited to windows.
It happened to me (much to my annoyance) in linux (mandrake 8.2) monday
I think it may be doing it because the lmb is released before the alt key…
Can’t test it here without changing config, and no time
will report back later
— edit 1 —
I can’t recreate the problem on this computer. If I find time tonight I will try it on that mandrake system again
It just happened to me too. I was in Linux. It’s the only time that it’s ever happened to me, so it seems like it’s a bit random, not necessarily a glitch in Blender.
Goo
I know it’s a glitch in the system, I just assumed it had something to do with blender because it happens a lot more often in blender than in anything else.
I can’t seem to recreate the problem, but it’s probably because I’m trying