Help Needed - or I´ll really go insane !!! PSE 7 not reinstalling

Hello  everyone out there;
First : Please excuse my bad english, I´m writing from Germany  and I don´t have a chance to practice my english very often.
I´m really going insane.
I own a Adobe PSE 7  ORIGINAL  Full Version. NO upgrade.
After a  Systemcrash a few days ago I tried to reinstall my PSE7 .
First : It won´ t install properly from the CD, no matter what and how often I tried it. There are a lot of files missing durig the installation, and  after the
file photoshop.exe is missing?
Then , when I tried to register it online  (  I didnt before ´cause all time  I was just  to lazy to do so, yes ) the registration suddenly told me :
You serial isn`t valid, because was registered before ! ( WTF ????? O.O ....HOW ????? I didn´t do that !!! Who could have registered with my serial number -  I am living on my own and nobody else uses my computer ?  )
Next : No chance for me to come in contact with the german support ? If I call the hotline, I´m stucking in this  *mumble *  telephone-computer-serviceline  for lightyears  without a chance to get out of the loop by choosing one of the offered numbers to press ????
I tried to reset computer => no effect
I tried to de - and reinstall all adobe products ....=> no effect
Now I can´t  reinstall Adobe reader 9 too ......
I don´t know what else I can try, but I am really so angry ( especially for no contact to german support ) that  I really wouldt like to go beserk !!!
Is someone out there who can help me ????


Newest update :
It didnt work. I found the processes the asked me to close , but i was not abled to shut them.
Although you told me to calm down,  I selected the least possible option:
I formatted  my harddisks and Installed a complete  new Windows XP Pro.
NOW the installation is running without any problems, the serial is working...
and I am happy again....
I´m sorry I can´t tell you "better " news  ( such as => OH, yes, the tip worked !!!)  bu at least I am able to use my PSE 7 again, and that was worth
3 Days of work
Thank you very much for your kindness and help.   That was great  !
with Greetings from Germany