Urgent !!! Vb Script solution needed....

Hello.
I am new to scripting & have a problem.
I have created a directory at -- "c:\test" which have 8 files namely
a1.txt, a2.txt, a3.txt, a4.txt, a5.txt, a6.txt, b1.txt & b2.doc (read extensions carefully)...

Now...From Start --> Run, run the command , run the script with following parameters :::
1. <file directory>, "a*.txt", 2
Files remaining should be a5.txt, a6.txt, b1.txt & b2.doc

2. Further, Start --> Run....
<file directory>, "a*.*", 2
Files remaining should be again .. a5.txt, a6.txt, b1.txt & b2.doc

3. Lastly, Start --> Run...
<file directory>, "*.*", 3
Files remaining should be a6.txt, b1.txt & b2.doc

I have tried a bit, but it deletes all files of .txt each time.....
plz help me & draft the vb script code ---- its Urgent !!!
Thanks.