well i have uploaded files in same location where previous installation was installed. I can see new files there using FTP, how can i get rid of server caching or should i remove internal_data/install-lock.php file?
Do not remove install-lock.php unless you intend on reinstalling (and removing all data). I don't think you want that.
If you're positive the files are uploaded in the correct location -- overwriting the old files -- then it will be the PHP opcode cache not refreshing on file changes. Restarting the web server/PHP-FPM should clear that up.