Three Little Problems For The Experts

assalam-o-alaikom everyone
first of all .. i wanna all of u to know that i had spent the last 35 minutes searching in the old threads for a problem similar to mine so that i'd avoid bothering u guys .. but since i found none, i planned to bother the experts of u a little to solve this little three nasty problems i have ..
Ok ppl .. here is my problem ... i'll be very thankful to whoever helps me out ASAP ..
this started a couple of weeks ago when i noticed some bizzare behavious during net surfing ..

sometimes while accessing some of my frequently visited pages like this montada or some others, a DNS error appears with the title Internet Optimizer .. furthermore, i had noticed a folder in my D drive called ddm that came out of no where and has a file in it named OPTIMIZE.EXE .. the thing common B|W these two is that they have the same icon .. i mean both the exe file and the internet optimizer window .. its somwthing like the Xupiter folder most of u must have had the same trouble .. i deleted the ddm folder, but i still get that nasty InternetOptimizer site opened when i try to access some of the pages .. anyone can help me out with this???
the second problem is that .. back few weeks ago, i had DLed PS8 from a chinese site the link to which i got from moon15.com .. the problem is that eversince then, my homepage changed to that of the chinese site called 58Q.com .. even if i reset it, it comes back if i reboot... how can i reset it for once and all???
thirdly and last .. i have a 40GB HD .. the total space used as i surely believe is no more than 15 GB .. and im definitly sure about this .. but when i come to check the total space used from the properties .. it says 32GB and thats almost not possible .. coz im damn sure its no more than 15 GB .. may be it no problem but sometimes .. when i install some stuff, it says im outta disk space .. hows that? i still have more than 20 GB free ..BTW .. just in case it mattered .. im using a WinXP Pro and have a DSL ..
thats all for noe hopefully .. any quick response will be highly appreciated ...
for those who will help me .. a heartily gratitude in advance
^_^
Thanks for reading till here
patiently waiting for replies

السلام عليكم
الصراحه اول مشكلتين ماعندي حل لهم
لكن الثالثه صارت لي ونزلت برنامج اسمه
Window washer
ولما استعملته حصلت 5 جيجا بايت زياده بعد ما البرنامج نظف الكمبيوتر :)
وهذي وصله لموقع البرنامج وفيه وصله للتنزيل
http://www.webroot.com/
حبيت اذكرج ان البرنامج تجريبي لمدة 30 يوم

http://download.com.com/3001-2144-10227352.html

this program must fix the 1st and the 2ed
its light and easy to use
scan
sellect
fix

زيادة على الخبراء
هل انت تستعمل Windows XP Pro (PIRACY)
كوبي؟