If its still the bloated factory preinstalled Windows 7 then that is a corrupt install to begin with, larded with sponsors' crapware and useless duplicate utilities which throttle and conflict with superior versions in Windows 7. That's why most tech enthusiasts prefer to Clean Reinstall - Factory OEM Windows 7
to get the best possible install instead of the worst one which you have. This will also obviously solve your boot problem. Just be sure to make your Recovery disks first so you can delete all partitions during the booted reinstall.
Until then you can remediate the problem some following these steps to Clean Up Factory Bloatware
especially establishing a Clean Boot to get the freeloaders off Windows 7's back, using a free lightweight AV suggested with the Windows 7 firewall, gradually dumping the programs you realize you don't need or want.
If you still need to troubleshoot the slow boot work through these Troubleshooting Steps for Windows 7
which will also help familizarize you with the system resources, logs, tools, hardware tests, and best practices.