re-installing ubuntu 12.04 crashes during language pack install

Some background info (prior to reinstall):

* Ubuntu first-time user, installed 12.04 alongside Windows 7 last month.
* Began experiencing extreme performance slowdown/monitor freeze while running Chrome.
* Problem persisted on other programs (Firefox, Software Center) after uninstalling Chrome.
* apt-get update/upgrade etc result in I/O error, followed by inability to boot Ubuntu.
* mounting and using media fix on partition restores the ubuntu boot capability, but returns with the same slowdown error.
* Windows 7 partitions continue to work fine.

On Reinstall:

* Reinstallation is unsuccessful, crashes halfway thru instead of a fresh version of Ubuntu 12.04

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: ubiquity 2.10.16
ProcVersionSignature: Ubuntu 3.2.0-23.36-generic-pae 3.2.14
Uname: Linux 3.2.0-23-generic-pae i686
ApportVersion: 2.0.1-0ubuntu5
Architecture: i386
CasperVersion: 1.315
Date: Tue May 22 10:24:34 2012
InstallCmdLine: noprompt cdrom-detect/try-usb=true file=/cdrom/preseed/ubuntu.seed boot=casper persistent initrd=/casper/initrd.lz splash -- BOOT_IMAGE=/casper/vmlinuz
LiveMediaBuild: Ubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423)
ProcEnviron:
 LANGUAGE=en_PH.UTF-8
 TERM=unknown
 PATH=(custom, no user)
 LANG=en_PH.UTF-8
 SHELL=/bin/bash
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)