Hilfe kann nichts mehr kopieren

Mal so als Zwischenhilfe:
Gehe in Registrierungseditor (Ausführen -> "regedit" -> Enter), dann in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows und rechts müsste da dann irgendwo ein Schlüssel sein, der pushow**.dll heißt, die beiden Sternchen sind irgendeine Zahl. Den Schlüssel einfach löschen.

Das ist ein Virus, der sich Pushow nennt, kommt von "popupshow". Hier auch nochmal das weitere Vorgehen teilweise beschrieben, sonst einfach mal googlen.

Zitat von http://kb.mozillazine.org/Clipboard_not_working

Removing AppInit_DLLS

Caution: While these steps should be safe to perform if followed correctly, you should never edit the registry if you don't feel confident or are unsure of what you are doing.

• Important! Close all Firefox, Opera and Internet Explorer windows.
• Click Start > Run…
• Type “regedit.exe” and press OK.
• Get to the following location in the registry: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows
• In the pane on the right-hand side of regedit you should see a String called “AppInit_DLLs”
• Take note of any value listed to the right of “AppInit_DLLs” as it may indicate you have malware installed.
• Right click on “AppInit_DLLs” and choose Delete.

[edit]
pushow

Pushow (pop up show), a malware, affects the clipboard through AppInit_DLLs. (See Bug 334500.) Infected computers have files "popupshow.dll" or "pushowxx.dll", where "xx" is a random number, within "C:\Windows\System32\". To check for infection, Windows users should enable "Show hidden files and folders", search for "pushow*" and "popupshow.dll" files, and delete these files. Deleting these files is not usually possible until AppInit_DLLs is removed. Anti-malware software may not detect pushow, even if the software's definitions are up to date. [1]