I have written a program, it uses a lot of replace funtions with huge amounts of texts.
Resultingly, It takes hell lot of time to operate.
Is there any way I can increase its speed?

Please post your code so that we can give another way of approach to your current problem.

OK, This is The Main Project. I apologize for it is roughly written. :$
Actually the buttons have to be pressed one after the other in the manner they are arranged, i.e., the sequence to do it right should be, save - load image - replace - load rtf file

You'll find out what it does, and For load rtf file - write "input.txt" for the file source

PS : I hope you have winrar or any other archiver with rar support :S

i do not open each and every file i come across in net ,sorry .

ok, but you can give me some ideas to operate strings faster. It takes insanely high time (never ending some times) with large chunks of text.

What are you trying to do with the strings? I don't open other people's code, either. VB can handle strings up to 32767 characters fairly fast if the algorithms are optimized. Beyond 32767 characters you need to use something like C. I've tried it and VB6 can get lost when the input is longer than 32767.