hal.dll Win 7

I recently installed sonar le. tested it and all worked fine. turned off my computer then when i restarted my computer win7 would not startup. I did a repair and it worked but Sonar LE was no longer installed and my download dissapeared. I waited again for the downloads. installed LE all over again (thinking that the problem was somthing else, how could it be sonar?) but as true as my blood boils now, it happened all over again. this time i chose to start my computer in a previouse version then i got a message saying
 
<windows root>\system 32\hal.dll
 
was corrupt or missing
 
I later found out through another website that win7 doesn't even use hal.dll...blah blah blah.
 
http://pcsupport.about.com/od/fixtheproblem/ht/hal-dll-missing-windows-7-vista.htm
 
I tried what it says to do and my computer still has the problem
 
I want to install Sonar LE (for wich i spent 60 bucks on in this financial crysis) without all these problems.
 
I just disabled auto restart and found a new message with a blue screen:
 
STOP: c0000135 The program can't start because %hs is missing from your computer.
Try reinstalling the program to fix this problem.
 
I dont understand how installing sonar LE can cause all this

Thanks for reply gregy
 
I dowloaded from cakewalk sonar. I had a trial version of producer. it (trial) ran out so i clicked to purchase. then just followed the links to purchase from sonar. I cant remember the version but being direct from sonar i'd imagine that its the latest as in X1 LE (not sure about vNo.). I downloaded a package that has "mp3activation", "Digital Sound Factory Free Cakewalk Sound Center Instruments Examples Pack.exe" and "SONAR_X1_Trial_Tutorial_Content.exe". (did so Just last week) (i do have the whole file)
 
Just an Idea. could it be that after the install of LE, the trial version was clashing with it somehow. because i dont think it automaticaly uninstalled the trial of sonar producer
 
Or is it my old sound card. But it worked fine before i shutdown my computer. (i installed and then tried it to make sure, as well as regestration)
 
Or maybe my antivirus because it did some updates and i hear that AVG has caused this on other systems and funny enough it only effected win7 64bit. I doubt it though because both times i installed Sonar this crashing happened. i have done heaps of searching on google.
 
My System:
Win7 64 (Home Premium)
Micro Trend Titanium (virus protection)
2.4 Q6600 (quad core)
Audigy 2 (soundblaster live, creative labs)
Nvidia GTX460
4gig ram
New 1T HDrive (no probs with it)
XFX nForcei SLI motherboard (disabled its onboard sound long before sonarLE)
 
I now know (i could still be wrong) that choosing to start in previouse version (refering to my first post) is just choosing to start in winxp and thus my computer is not configured to do that (why then does it give me the option...just thinking out loud)

Thanks Greg

I'm not sure what caused it but i have installed win7 again on my second hardrive and patched it then installed the program. Its working fine. but i have no idea how to get my original windows7 working again. I ran virus check and got 3. One called windows assembly GAC_32