how do I get rid of BO:Writable

From the link above you'll see you need to run HijackThis 2.02:
http://majorgeeks.com/Trend_Micro_HijackThis_d5554.html

Create a folder where you would like the HijackThis file to reside and run it from there, not from the Desktop or a temporary folder.
Run the scan & save the logfile.  Then click the "Attach Code Snippet" box, paste the logfile into the "Code Snippet" page & there we can analyse it.  

After running HijackThis it's probable you'll need to run Combofix to resolve it.
Download ComboFix and save to your Desktop >
http://download.bleepingcomputer.com/sUBs/ComboFix.exe

Before using ComboFix please disable any realtime Anti-virus, Anti-spyware, Shields, etc. that you may have running, and remember to re-enable them later, upon completion.

Double click "combofix.exe" and follow the prompts.
When it's finished it will have produced a Logfile, probably at C:\ComboFix.txt.
You could post that log together with a HijackThis log, in a reply for us.
Please do not mouseclick Combofix's window while it is running, because it may stall.  It is absolutely normal for you to see a blue screen with flashing cursor, and this can last for up to 30 mins.  Just let it run.

ComboFix does present a slight risk to your system, but it's worth considering, especially if HijackThis finds nothing & yet you are quite heavily infected.